Depends on the state and how much your income was cut
Can I File For Unemployment If My Salary Is Cut But My Hours Stay The Same?
Unemployment insurance is for someone who has lost their job through no fault of their own. Because your salary was lowered and you're still working,that means you're employed,so you can't receive unemployment.
If you are a salary employee and your salary is cut without your hours. Are you now considered hourly under Federal Labor Laws?